One form of tube flaring tools commercially available comprises a pair of elongated bars which cooperate to define a plurality of openings of various sizes between them. Each opening is respectively sized to receive a tube of a standard size and to permit the bars to grip the tube when the bars are pressed toward each other. Various devices are utilized to so press the bars together. The tubing is then so gripped while a flaring cone is forced against the end of the tube to flare that end.
The device for forcing the bars together has two primary requirements, namely, (1) it must develop sufficient force urging the bars together to securely hold the tube between the bars, and (2) it should be readily operable to apply and release that pressure. These two requirements are not entirely consonant. Thus as the flaring cone is pressed against the end of the tube, the force so applied tends to cause the tube to slide out from between the bars. To offset this tendency, considerable pressure must be applied urging the bars together so as to securely hold the tube against slippage. When utilizing bolts at each end of the bars, which bolts have wing nuts on them (as is a common practice), for developing this pressure, it is necessary to tighten the wing nuts very tight. This is difficult, both in the tightening and in the loosening of the nuts.
An additional disadvantage of such devices commercially available is that it may be time-consuming to place the yoke (on which the flaring cone is mounted) onto the bar. The bolts and nuts on the ends of the bars, when in place, prevent the yoke from being slid onto the bars from the ends. While in most such devices, the yoke may be rotated approximately 90.degree. from the position in which it is used and then fitted onto or off the pair of bars, this requires that the flaring cone be backed off substantially from the position at which it is used during the flaring operation. So backing off the flaring cone and subsequently moving it into working position can be time-consuming.
The principal object of the present invention is to provide an arrangement whereby the yoke serves to cam the bars together during the flaring operation. This eliminates the necessity of a separate device for this purpose, such as the bolts and wing nuts previously referred to. The more force that the flaring cone applies to the end of the tube, the greater will be the camming pressure urging the bars together about the tube being flared. Furthermore, this pressure is applied directly at the location of the tube being gripped, rather than at a remote location such as occurs with the bolts and wing nuts previously referred to. Since there are no bolts and wing nuts at the ends of the bars, the yoke can easily be moved off the ends of the bars in a direction longitudinally thereof.
In a further aspect of this invention, there is a centrally located bolt and wing nut employed to initially press the bars together sufficiently to hold a tube between them until the yoke is in place and the flaring force commences. Of course, as the flaring force commences applying pressure to the end of the tube, it initiates the camming action to press the bars together to resist tendency of the flaring force to move the tube out from between the bars.
Further objects and advantages will become apparent from the following description and the appended drawing.